So, I have two pairs of boots. Both size 13. Both fit my right foot like a glove. No heel lift, no pressure points, no cramped toe box, nothing. Perfection all damn day.
Now my left foot, for whatever reason, appears to be slightly smaller than my right because I have pretty nasty heel lift and way to much play in them then I'd like. The left still doesn't have pressure points or toe cramp issues but I just can't seem to fix the gross heel lift that occurs every time I go toe side.

Wondering if there are any fellow boarders with my same situation, and if so, how they remedied the problem.
Does any company out there allow you to mix/match sizes?
Seems like I'm a 13 in my right foot and a 12 in my left.
Boots I have now are DC: Phase and thirtytwo: STW BOA

My left foot is also slightly smaller than my right, although not by an entire size. Maybe a quarter-size, or a half-size at most. When I buy regular shoes, I make sure the right is comfortable, and then the left is usually OK, if not quite perfect. With things like snowboard boots or ice skates, however, I try both on, then make a judgment based on the way the set fits. Having the right just a little bit too snug is better than having the left too loose. Fortunately, boots tend to pack out, so in my case the slight discrepancy usually can be overcome by differential packing. That might not work for a full size.

You may want to try a separate pair of heat-moldable liners. That should give you a custom fit for each foot. Use a toe cap on the right if it needs more room.